1. Field of the Invention
The present invention relates to mortise locks that extend multiple bolts outward from a door edge and into latching engagement with an adjacent surface, such as an adjacent door frame. More specifically, the present invention relates to mortise lock assemblies that include a central mortise lock having a deadbolt that extends outward from a face piece mounted to the edge of a door and at least one latch mechanism having a latching bolt, preferably a hook bolt, which also extends outward from the face piece to engage the adjacent surface.
2. Description of Related Art
Mortise locks are designed to be mortised into the edge of a door and typically include a spring loaded latchbolt with a beveled edge that latches into an opening in an adjacent surface when the door is closed. The adjacent surface may be a door frame or the edge of another door. In addition to the latchbolt, mortise locks usually include an integrated deadbolt that can also be extended outward from the mortise lock to latch into the adjacent surface.
In most modern mortise lock designs, the deadbolt can be extended or retracted by turning a key in a cylinder lock on one side of the door, or by rotating a thumb latch on the other side. The deadbolt may also be connected to the latchbolt retraction linkage between a handle and the latchbolt. When the door is locked, rotating the handle will retract the latchbolt and simultaneously retract the deadbolt.
An improved type of mortise lock used in high security applications is a multipoint mortise lock assembly. A multipoint mortise lock assembly includes an elongated vertical face piece that is attached to the front of the mortise lock case. One or more additional latch mechanisms are also attached to the face piece and are operably connected to the mortise lock. The additional latch mechanisms include latching bolts that can be extended outward from the face piece and into latching engagement with the opposing door frame or adjacent door.
For maximum security, the additional latch mechanisms are constructed with hook bolts which hook into openings in the opposing door frame when they are extended. This hooking action prevents the adjacent door frame from being separated from the face piece on the mortise lock assemble until the hook bolts are withdrawn.
Multipoint mortise lock mechanisms of this type have heretofore required that the lock be operated with two hands to extend the hook bolts. One hand is required to rotate the key, and a second hand is required to operate the hook latches. The hook latches are usually operated by rotating the handle, typically a lever handle, at the same time that the key is held in a selected position that permits the extension of the hook bolts. Two-handed operation, however, is inconvenient and the correct manner of operating the lock may not be immediately apparent to the user.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a multipoint mortise lock assembly that can be operated with one hand.
It is another object of the present invention to provide a multipoint mortise lock assembly that may be mounted to a door having a beveled edge.
A further object of the present invention is to provide a multipoint mortise lock assembly that can be operated by existing trim and handle mechanisms.
Still another object of the present invention is to provide a multipoint mortise lock assembly that is easy to operate and which operates in substantially the same manner as conventional mortise locks having only a latchbolt and a deadbolt.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.